This study aims to investigate the mechanical properties of a rotator cuff tear repaired with a polypropylene interposition graft in an ovine infraspinatus ex-vivo model.

Twenty fresh shoulders from skeletally mature sheep were used in this study. A tear size of 20 mm from the tendon joint was created in the infraspinatus tendon to simulate a large tear in fifteen specimens. This was repaired with a polypropylene mesh used as an interposition graft between the ends of the tendon. Eight specimens were secured with mattress stitches while seven were secured to the remnant tendon on the greater tuberosity side by continuous stitching. Remaining five specimens with an intact tendon served as a control group. All specimens underwent cyclic loading with a universal testing machine to determine the ultimate failure load and gap distance.

Gap distance increased with progressive cyclic loading through 3000 cycles for all repaired specimens. Mean gap distance after 3000 cycles for both continuous and mattress groups are 1.7 mm and 4.2 mm respectively (P = .001). Significantly higher mean ultimate failure load was also observed with 549.2 N in the continuous group, 426.6 N in the mattress group and 370 N in the intact group.

The use of a polypropylene mesh as an interposition graft for large irreparable rotator cuff tears is biomechanically suitable and results in a robust repair that is comparable to an intact rotator cuff tendon. When paired with a continuous suturing technique, it demonstrates significantly resultant superior biomechanical properties that may potentially reduce re-tear rates after repairing large or massive rotator cuff tears.

Multiple studies have shown that the symptomatology of knee osteoarthritis weakly correlate to radiographic severity of disease. Current literature however does not have much in the way of comparing functional outcomes of those with OA knees with radiographic severity. Our objective was to compare radiographic measurements of OA knees with self-reported functional outcomes and determine if radiographic severity of OA knees correlated with loss of functional ability.

A retrospective review of prospectively collected registry data of 305 patients with osteoarthritis of the knee was collected. The patient's x-rays were reviewed, and radiographic measurements were taken to include medial, lateral and patellofemoral joint space distance measured in millimetres. The Kellgren and Lawrence, and Ahlback classifications of radiographic knee OA were computed. These were correlated with severity of functional limitations was measured using the SF36, Knee society score (KSS) and Oxford knee scores.

Statistical analysis were conducted with SPSS V22.0 statistical software. Demographic characteristics and functional assessments were analysed using one way ANOVA test. Post-hoc test using Tukey HSD and effect size (partial-eta squared η²) was performed if one-way ANOVA was found to be statistically significant. A p-value of 0.05 or less was considered statistically significant.

Pre-operative patient demographics are shown in table 1. Patients in with Grade 2 osteoarthritis were significantly younger than Grade 4 patients (post-hoc p=0.003). There were no statistically significant differences in age between the other Grades, and there were no differences in BMI or gender or operative site between all grades.

There were significant differences in KSS Function scores between Grade 2 and Grade 3 patients (post-hoc p=0.017) and Grade 2 and 4 patients (post-hoc p < 0 .001). Statistically significant differences were also found between Grade 1 and Grade 4 patients for the KSS Knee score (post-hoc p=0.016). There were significant differences in Oxford knee score (post-hoc p=0.026) and SF- Physical Function (post-hoc p < 0 .001) between Grade 2 and Grade 4 patients too.

The effect size η² for KSS Function, KSS Knee and Oxford knee score was 0.05, 0.06 and 0.33 respectively. When comparing the loss of joint space with the functional scores, there were no statistically significant correlations. Our study show that the radiological severity of knee osteoarthritis based on the two scoring methods was able to correlate with worsening functional scores. Most notably, the differences in KSS function scores correlated strongly between Grade 2 and Grade 3 patients. Of note, there was no correlation between the loss of joint space and the severity of functional limitations across any of the scoring systems. Our study showed that although both the Kellgren and Lawrence and Ahlback radiological grading of Osteoarthritis were able to correlate with worsening functional scores, this was not due to loss of joint space alone and further studies need to be conducted on the other contributors to the scoring system such as osteophytes and subchondral sclerosis.

Our study show that the radiological severity of knee osteoarthritis based on the two scoring methods was able to correlate with worsening functional scores. Most notably, the differences in KSS function scores correlated strongly between Grade 2 and Grade 3 patients. Of note, there was no correlation between the loss of joint space and the severity of functional limitations across any of the scoring systems. Our study showed that although both the Kellgren and Lawrence and Ahlback radiological grading of Osteoarthritis were able to correlate with worsening functional scores, this was not due to loss of joint space alone and further studies need to be conducted on the other contributors to the scoring system such as osteophytes and subchondral sclerosis.

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Introduction

Cobalt chrome femoral head has been used widely in total hip arthroplasty and has shown favorable outcome. However, there is still of concern of potential metal toxicity from the wear debris. In the other hand, titanium is well known for its biocompatibility but it is not used in bearing surface of arthroplasty due to its brittleness. Recently, coating of the prosthesis using plasma electrolytic oxidation (PEO) has shown favorable surface protection. Thus, in this study, we tried to find out whether the PEO coating on the titanium surface would provide surface protection.

Patient outcomes using the Scoliosis Research Society (SRS) questionnaire after thoracoscopic and posterior surgical techniques for thoracic idiopathic scoliosis were compared after > 2 years post-op. Additional comparisons were made with non-operated scoliosis and normal patients. Our objective was to determine if scoliosis surgery and surgical technique used to treat a cohort of patients with the same type of scoliosis deformity affects patient outcome. The SRS-24 questionnaire was prospectively administered to 4 groups of patients:

42 patients with thoracic idiopathic scoliosis who underwent thoracoscopic instrumented fusion surgery (thoracoscopic group);

The 2 surgical groups were comparable with regards to age at surgery, pre-op Cobbo and follow-up. SRS-24 domian scores were computed for all 4 groups and were compared on SPSSv13 software. Our results show the thoracoscopic group having a significantly smaller mean post-op Cobbo (17° vs 25.1°, respectively; p< .001), which was achieved using less fusion segments (7 vs 9.3 segments, respectively; p< .001). The mean Cobbo of the scoliosis control group was significantly larger than the post-op Cobbo of the thoracoscopic group (p< .001), and was comparable to the post-op Cobbo of the posterior group. Comparing the 2 surgical groups, the thoracoscopic group showed trends towards better scores in 4 of the SRS-24 domains compared to the posterior group, but this only reached statistical significance for the satisfaction domain (p< .05). When comparing the 4 groups, Pain scores of both surgical groups were similar to those who did not have surgery, and were worse than normal patients (p< .0001); Self-image scores after surgery were higher than those who did not have surgery(p< .05) and were comparable to normal patients; Function and Activity scores of the thoracoscopic group was significantly inferior to the scoliosis control group (p< .05). Our study demonstrates that > 2 years after surgery, both thoracoscopic & posterior surgery resulted in pain scores that were similar to patients with scoliosis that did not have surgery, and were worse than the normal group. However, both surgical techniques resulted in self-image scores that are comparable to normal individuals despite a difference in post-op Cobbo. When comparing the two surgical techniques, the SRS-24 showed no difference between the 2 surgical techniques, except for patient satisfaction which was better in the thoracoscopic group.